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United States Patent 3,140,698 HYDRAULIC TAPPET UNIT INVERTED Carl Voorhies, 917 S. Knight, Park Ridge, Ill. Filed Apr. 13, 1962, Ser. No. 187,366 Claims. (Cl. 123-90) This invention relates to a hydraulic lash adjuster assembly for use in internal combustion engines. It has for one object to provide a lash adjuster unit comprising a number of relatively movable parts which may be inserted as a unit into an existing engine and into valve mechanism parts or operating means already in existence. It may, of course, be used initially in comparable engines.

It has for another object to provide a mechanism of the type indicated which will operate as a hydraulic lash adjuster in the valve operating gear of an internal combustion engine and which will provide a means for minimizing the entrapment of air and for disposing of air which may enter entrained in lubricant entering the assembly, or otherwise.

Other objects will appear from time to time throughout the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings wherein:

FIG. 1 is an elevation with parts in section showing the unit of the present invention in one suitable installation;

FIG. 2 is a vertical section on an enlarged scale showing the unit of the present invention; and

FIG. 3 is a detailed sectional view showing a modified form of the device and showing only the upper end of the lash adjuster.

Like parts are designated by like characters throughout the specification and drawings.

Mounted in FIG. 1 there is shown with the unit only so much of an engine installation as is necessary to indicate the general location of the device of the invention. Thus 1 is a rocker arm mounted to rotate about the member 2. A lubrication passage 3 is positioned centrally of the member 2 and lubricant may pass from it through a duct 4 to a duct 5 in the arm 1.

The arm 1 is provided with an interiorly threaded boss 6 with which the duct 5 communicates. An adjusting screw 7 is screwed into the threads Within the hollow portion of the boss 6. At its upper end it may be provided with a lock nut 8. At its lower end it is provided with a generally hemispherical head 9. Centrally the adjusting screw is provided with a reduced portion 10 which may have a perforation 11 formed through it. The perforation 11 communicates with a duct 12 which extends to the outer end of the head 9.

The head 9 is received in a hemispherical depression in a hardened insert 13 which is perforated as at 14.

The insert 13 is received in a bridge 15. The bridge has formed within it two pockets or depressions 16, 16, a transverse lubricant passage 17 and a lubricant passage 18 which connects the passage 17 with the cup or hemispherical depression formed in the insert 13. A stem 19 is connected to the bridge 8 and is supported in a known manner.

In the particular forms shown two valve stems 20, 20 appear and two units of the present invention are inserted, one in each of the pockets or depressions 16 of the bridge. As shown these units comprise housing 21 with lateral shoulder-forming members 22. They may be reduced as at 23.

A reicprocating cylinder 24 is positioned for sliding movement within the housing 21 and is provided with a preferably rounded working face 25. A lock ring 26 positioned adjacent the upper edge of the cylinder 24 prevents separation of the cylinder downwardly from the housing.

3,14%,698 Patented July 14, 1964 A hollow plunger 27 is positioned for reciprocation within the cylinder 24. At its upper end it carries a working face member 28 which is rounded as shown and contacts, when in place, the inner surface of the upper face of the cavity 16. The member 28 is provided with an inward reduced extension 29 and may be grooved as at 30 to receive a locking ring 31. This ring bears against the inner face of the hollow plunger 27, which plunger is shaped to form a chamber 32 within itself. The wall of the plunger 27 is perforated as at 33 so that oil may enter it. At its lower end the plunger is reduced as at 34 and provided with an outlet passage 35 which is closed by a generally flat valve 36 having an integral downward extension 37. A cage 38 engages the valve 36 and is positioned upon the outward face of the extension 34. A spring 39 is positioned within the cylinder and bears upon a flange 40 of the cage 38 and also upon a shoulder 41 formed by the reduced portion 34.

If desired an air bleed hole 42 may be formed in communication with each of the cavities 16. One such air bleed hole is shown in FIG. 2. This may be present or may be omitted as desired.

In the form of FIG. 3 the cavity within the bridge differs in shape from that of FIGS. 1 and 2 and permits a different construction of the lash adjuster. As shown in FIG. 3 the bridge is provided with a cavity 44 which has a flat inner top surface 45 from which leads an air bleed hole 46.

The upper end of the lash adjuster plunger 27 is the same as that shown in FIGS. 1 and 2 but the closure or working face 28, which is shown in detail in FIG. 2, is omitted and there is no closure member for the lash adjuster plunger 27. Its open upper end bears against the flat face 45 of the cavity 44 and is adequately sealed by its contact with that flat face at that point so that oil from within the plunger does not escape through the air bleed hole.

As shown in FIG. 3, the hole 46 is closed by the upper edge of the plunger 27 and While there will be suificient relative movement of the parts to permitthe bleeding out of air through the hole 46, oil will not escape therethrough in quantities sufi'icient to make operation of the parts unsatisfactory.

In the assembly of the device of this invention the guide or bushing 21 acts as an adapter and makes it possible to insert the device as a unit into the bridge of the valve gear and makes it interchangeable with existing conventional tappet or lash adjuster units which may have been used in connection with such bridges. The guide or bushing 21 is inserted into the cavity 16 preferably with a press fit. The lash adjuster cylinder 24 is held against separation from the member 21 by the lock wire 26. Thus in assembly of the device and mounting it in a bridge the cylinder 24 cannot fall from the member 21 and the hollow piston 27 is installed in the cylinder 24, as shown in FIG. 2 in particular. The closure 23 inthe form of FIGS. 1 and 2 is loose, as shown in FIG. 2, because the lock ring 31 does not completely fill the groove 30. Thus the closure 28 may adjust itself to the conical top of the cavity 16 and may move laterally to some degree with respect to the plunger or piston 27 in which it is loosely mounted, and thus it avoids putting lateral stresses upon the plunger 27 or the cylinder 24.

It is recognized that in quantity production procedures a certain amount of tolerance and play are necessary and should the member 28 be tight in the piston or plunger 27, it is possible that the plunger 27 or the cylinder 24 would be subjected to lateral or angular stress or loads. This is avoided by using the floating closure 28 which provides a self-aligning means to prevent such lateral or angular loads. It thus cooperates in accomplishing one purpose of the invention, namely that of providing a replaceable lash adjuster unit which is insertable with the open end of the cylinder 24 upward so that air can escape and the device is also self-aligning. The press fitting of the guide or bushing 21 into the bridge does not distort the member 21 sufiiciently to prevent free motion of the cylinder 24 and does not distort the cylinder itself to prevent free movement of the piston or plunger 27, and hence proper operation of the hydraulic unit as a whole is insured by the use of the member 21. The utility of the device is not limited to the precise details of the hydraulic lash adjuster unit. The adaptability of the device could be embodied in lash adjusters having other structural details than those shown herein.

In the form of FIG. 3, instead of the cavity 16 with a generally conical upper end, a cavity 44 might be used as shown in FIG. 3 and when thus used the upper wall of this cavity 44 will be flat as shown. In that arrangement no closure is necessary for the upper end of the piston or plunger 27 which, as shown in FIG. 3, may abut directly against the flat face 45 at the upper end of the cavity 44. In this form of the device instead of the hole 42 of FIG. 2 a hole or passage 46 may used and this serves as an air bleed hole through'which air or gas which accumulates in the system may be expelled. There is sufficient movement of the plunger or piston to permit air to escape through the bleed hole or passage 46.

Although an operative form of the device has been shown, the invention is not limited to the particular details shown. Many changes may be made in the form, shape and arrangement of parts without departing from the spirit of the invention.

I claim:

1. A hydraulic lash adjuster unit, said unit comprising a guide insertable in a closed-end cavity of a movable element of a valve actuating linkage, a cylinder mounted therein for reciprocation, means preventing separation of said cylinder from said guide, a hollow piston mounted within said cylinder for reciprocation, an opening in one end of said piston, the opposite end of said piston being closed by a member shaped with a rounded exterior surface portion disposed to engage the closed end of said cavity when the unit is inserted therein, said piston being perforated in its wall, there being clearance between said piston and the adjacent wall of said cylinder adapted to establish a passage to the interior of said piston.

2. A hydraulic lash adjuster unit, said unit comprising a guide insertable into a closed-end cavity of a movable element of a valve actuating linkage, a cylinder mounted therein for reciprocation, means preventing separation of said cylinder from said guide, a hollow piston mounted within said cylinder for reciprocation, an opening in one end of said piston, the opposite end of said piston being closed by a member loosely fitted within the end of said piston and being relatively movable with respect thereto and shaped with a rounded exterior surface portion disposed to engage the closed end of said cavity when the unit is mounted therein, said piston being perforated in its wall, there being clearance between said piston and the adjacent wall of said cylinder adapted to establish a passage to the interior of said piston.

3. A hydraulic lash adjuster unit insertable into a closed-end cavity of a movable element of a valve actuating linkage, said unit comprising a guide, a cylinder mounted therein for reciprocation, means preventing separation of said cylinder from said guide, a hollow piston mounted within said cylinder for reciprocation, an opening in one end of said piston, a valve positioned to close said opening, the opposite end of said piston being closed by a member loosely fitted within the end of said piston and relatively movable with respect thereto and shaped with a rounded exterior surface portion, means for frictionally restraining relative movement between said closure member and said piston, said piston being perforated in its walls, there being clearance between said piston and the adjacent wall of said cylinder adapted to establish a passage to the interior of said piston.

4. A hydraulic lash adjuster unit insertable into a closed-end cavity of a movable element of a valve actuating linkage, said unit comprising a cylindrical open ended guide, a cylinder positioned for movement therein, said cylinder having one end closed, the opposite end of said cylinder being open, a hollow plunger positioned within said cylinder for reciprocation and extending outwardly partially therefrom through the open end thereof, means within said cylinder biased to move said plunger outwardly with respect to said cylinder, the outwardly extending end of said plunger being provided with a closure member loosely fitted within said plunger extending beyond the end of said plunger and shaped on its exposed end with a convex portion disposed to engage the closed end of said cavity when the unit is inserted therein, means on said cylinder preventing its downward displacement from said guide, means engaging said plunger closure and frictionally preventing its displacement from said plunger, said lash adjuster unit including said guide, said cylinder and said plunger, being insertable upwardly into a downwardly open cavity in a movable element of a valve actuating linkage, the closed end of said cylinder, when the unit is inserted within said cavity, extending downwardly beyond the end of said guide.

'5. A hydraulic lash adjuster unit insertable into a closed-end cavity of a movable element of a valve actuating linkage, said unit comprising a guide, a cylinder mounted therein for reciprocation, means preventing separation of said cylinder from said guide, a hollow piston mounted within said cylinder for reciprocation, an opening in one end of said piston, the opposite end of the piston being closed by a member having an exterior end surface disposed to engage the closed end of said cavity when the unit is mounted therein, said closure being loosely fitted within said piston and movable relative thereto, said piston being perforated in its wall, there being clearance between said piston and the adjacent wall of the cylinder adapted to establish a passage to the interior of said piston.

References Cited in the file of this patent UNITED STATES PATENTS 2,036,936 Halford Apr. 7, 1936 2,237,854 Voorhies Apr. 8, 1941 2,380,051 Kettering July 10, 1945 2,665,669 Ellis Jan. 12, 1954 2,682,865 Voorhies July 6, 1954 

1. A HYDRAULIC LASH ADJUSTER UNIT, SAID UNIT COMPRISING A GUIDE INSERTABLE IN A CLOSED-END CAVITY OF A MOVABLE ELEMENT OF A VALVE ACTUATING LINKAGE, A CYLINDER MOUNTED THEREIN FOR RECIPROCATION, MEANS PREVENTING SEPARATION OF SAID CYLINDER FROM SAID GUIDE, A HOLLOW PISTON MOUNTED WITHIN SAID CYLINDER FOR RECIPROCATION, AN OPENING IN ONE END OF SAID PISTON, THE OPPOSITE END OF SAID PISTON BEING CLOSED BY A MEMBER SHAPED WITH A ROUNDED EXTERIOR SURFACE PORTION DISPOSED TO ENGAGE THE CLOSED END OF SAID CAVITY WHEN THE UNIT IS INSERTED THEREIN, SAID PISTON BEING PERFORATED IN ITS WALL, THERE BEING CLEARANCE BETWEEN SAID PISTON AND THE ADJACENT WALL OF SAID CYLINDER ADAPTED TO ESTABLISH A PASSAGE TO THE INTERIOR OF SAID PISTON. 